Wagons for carrying earth, ore, rubble, and other excavated material are well-known. It is also known to connect such a wagon to a tractor by means of a gooseneck affixed to the wagon and pivotally mounted on the tractor for pivoting about a vertical axis, with the gooseneck affording clearance above the rear wheels of the tractor. Various external means may be used for loading the wagon, and the wagon generally includes some means for moving the load from the wagon. The bodies of some wagons are arranged to be tipped up simply to dump the load carried thereby, whereas other wagons have positive ejecting means.
Such ejecting means may include a wall or plate of generally vertical disposition which is movable horizontally to eject the load from the wagon. Tremendous amounts of power are needed to move an ejector of this nature, as the load must be moved bodily across the floor of the wagon for dumping. It is known to use hydraulic cylinders for this purpose, but the ejector must be moved many feet, and this leads to extended cylinder-piston arrangements which are many feet long, and which in the past have been susceptible to damage, such as by a front end loader when loading the wagon. Such cylinder arrangements also are quite vulnerable to damage when the tractor-wagon unit must be maneuvered close to rock walls.
Problems also have been encountered with bending movements produced by the cylinders and the reaction of the load tending to pivot the ejector plate or wall about the movable mounts or guides therefore.
It is necessary to provide a movable closure opposite to the ejector wall so that materials can be retained for transport and then can be ejected from the wagon. Prior art closures for such ejection openings have therefore not been entirely satisfactory.
Relevant patent art on prior ejector wagons of the type heretofore discussed includes T. L. R. Hardwick U.S. Pat. Nos. 3,352,439 and 3,941,260.